Mirror, Mirror on the wall, are you the most-evil of them all? This is a question, 25-year-old Natasha keeps asking a haunted mirror, an exhibit that is waiting to be auctioned in the gallery she works at. Standing there in front of that mirror, she trails down the memory lane... Alex Merchant (Adil Hussain), an artist by profession settled in London lives happily with his wife Liza (Lisa Ray) and kids Natasha (Huma Qureshi) and Kabir (Saqib Saleem). Meanwhile, Alex falls out of love with Liza and gets involved with one of his models. His family knows about his extra-marital relationship.
In the meantime, Alex buys an antique mirror and soon after his life changes upside down. Many centuries ago, in ancient Britain, a woman, accused of practising witchcraft was burnt at the stake and her spirit was captured in the mirror. The spirit of the mirror kills whoever owns the mirror. The mirror’s spirit Anna(Madalina) hypnotizes Alex, who falls in love with her and promises to ‘kill and die for her’. The spirit asks Alex to kill his family and to prove his love for her. Convinced by the ghost, Alex kills his wife and in turn, Kabir shoots Alex. And in a fraction of a few seconds, their life changed forever. Kabir is committed to psychiatric care. Natasha herself is left fending for herself.
The grown-up Natasha is all set to avenge her parent’s death. After years of research about the mirror she has learnt about the spirit that resides inside and has ‘made arrangements’ to destroy the mirror because the mirror manipulates with the minds of those who try to destroy it and in this way is capable of protecting itself. Natasha decides to prove her brother innocent by telling the truth to everyone through a recording but things aren't in her favour.
While the movie starts showing the characters of Huma and Saqib as adults, the theme of Dobaara rests on an old tragic episode that keeps getting unfolded as the film proceeds. Natasha believes that the mirror is possessed by an evil spirit, which killed her parents. But Kabir wants to appear practical, and so he initially rejects his sister's claims. Nevertheless, after their parents were killed by the spirit, Natasha and Kabir had promised each other to destroy the mirror when they grow up. Hence, the two team up again to finish the task, and face the evil power face-to-face.
The climax takes an interesting turn as it actually keeps the essence of the title and history does repeat itself for Kabir.